/*
 * Copyright (c) 2008 Princeton University
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Authors: Niket Agarwal
 */

#include "mem/ruby/network/garnet-fixed-pipeline/SWallocator_d.hh"
#include "mem/ruby/network/garnet-fixed-pipeline/Router_d.hh"
#include "mem/ruby/network/garnet-fixed-pipeline/InputUnit_d.hh"
#include "mem/ruby/network/garnet-fixed-pipeline/OutputUnit_d.hh"
#include "mem/ruby/network/garnet-fixed-pipeline/GarnetNetwork_d.hh"

SWallocator_d::SWallocator_d(Router_d *router)
{
        m_router = router;
        m_num_vcs = m_router->get_num_vcs();
        m_vc_per_vnet = m_router->get_vc_per_vnet();

        m_local_arbiter_activity = 0;
        m_global_arbiter_activity = 0;
}

void SWallocator_d::init()
{
        m_input_unit = m_router->get_inputUnit_ref();
        m_output_unit = m_router->get_outputUnit_ref();

        m_num_inports = m_router->get_num_inports();
        m_num_outports = m_router->get_num_outports();
        m_round_robin_outport.setSize(m_num_outports);
        m_round_robin_inport.setSize(m_num_inports);
        m_port_req.setSize(m_num_outports);
        m_vc_winners.setSize(m_num_outports);

        for(int i = 0; i < m_num_inports; i++)
        {
                m_round_robin_inport[i] = 0;
        }

        for(int i = 0; i < m_num_outports; i++)
        {
                m_port_req[i].setSize(m_num_inports);
                m_vc_winners[i].setSize(m_num_inports);

                m_round_robin_outport[i] = 0;

                for(int j = 0; j < m_num_inports; j++)
                {
                        m_port_req[i][j] = false; // [outport][inport]
                }
        }
}

void SWallocator_d::wakeup()
{
        arbitrate_inports(); // First stage of allocation
        arbitrate_outports(); // Second stage of allocation

        clear_request_vector();
        check_for_wakeup();

}

void SWallocator_d::arbitrate_inports()
{
        // First I will do round robin arbitration on a set of input vc requests
        for(int inport = 0; inport < m_num_inports; inport++)
        {
                int invc = m_round_robin_inport[inport];
                m_round_robin_inport[inport]++;

                if(m_round_robin_inport[inport] >= m_num_vcs)
                        m_round_robin_inport[inport] = 0;
                for(int j = 0; j < m_num_vcs; j++)
                {
                        invc++;
                        if(invc >= m_num_vcs)
                                invc = 0;
                        if(m_input_unit[inport]->need_stage(invc, ACTIVE_, SA_) && m_input_unit[inport]->has_credits(invc))
                        {
                                if(is_candidate_inport(inport, invc))
                                {
                                        int outport = m_input_unit[inport]->get_route(invc);
                                        m_local_arbiter_activity++;
                                        m_port_req[outport][inport] = true;
                                        m_vc_winners[outport][inport]= invc;
                                        break; // got one vc winner for this port
                                }
                        }
                }
        }
}

bool SWallocator_d::is_candidate_inport(int inport, int invc)
{
        int outport = m_input_unit[inport]->get_route(invc);
        int t_enqueue_time = m_input_unit[inport]->get_enqueue_time(invc);
        int t_vnet = get_vnet(invc);
        int vc_base = t_vnet*m_vc_per_vnet;
        if((m_router->get_net_ptr())->isVNetOrdered(t_vnet))
        {
                for(int vc_offset = 0; vc_offset < m_vc_per_vnet; vc_offset++)
                {
                        int temp_vc = vc_base + vc_offset;
                        if(m_input_unit[inport]->need_stage(temp_vc, ACTIVE_, SA_) && (m_input_unit[inport]->get_route(temp_vc) == outport) && (m_input_unit[inport]->get_enqueue_time(temp_vc) < t_enqueue_time))
                        {
                                return false;
                                break;
                        }
                }
        }
        return true;
}


void SWallocator_d::arbitrate_outports()
{
// now I have a set of input vc requests for output vcs. Again do round robin arbitration on these requests
        for(int outport = 0; outport < m_num_outports; outport++)
        {
                int in_port = m_round_robin_outport[outport];
                m_round_robin_outport[outport]++;

                if(m_round_robin_outport[outport] >= m_num_outports)
                        m_round_robin_outport[outport] = 0;

                for(int inport = 0; inport < m_num_inports; inport++)
                {
                        in_port++;
                        if(in_port >= m_num_inports)
                                in_port = 0;
                        if(m_port_req[outport][in_port]) // This Inport has a request this cycle for this port
                        {
                                m_port_req[outport][in_port] = false;
                                int invc = m_vc_winners[outport][in_port];
                                int outvc = m_input_unit[in_port]->get_outvc(invc);
                                flit_d *t_flit = m_input_unit[in_port]->getTopFlit(invc); // removes flit from Input Unit
                                t_flit->advance_stage(ST_);
                                t_flit->set_vc(outvc);
                                t_flit->set_outport(outport);
                                t_flit->set_time(g_eventQueue_ptr->getTime() + 1);
                                m_output_unit[outport]->decrement_credit(outvc);
                                m_router->update_sw_winner(in_port, t_flit);
                                m_global_arbiter_activity++;

                                if((t_flit->get_type() == TAIL_) || t_flit->get_type() == HEAD_TAIL_)
                                {
                                        m_input_unit[in_port]->increment_credit(invc, true); // Send a credit back along with the information that this VC is not idle
                                        assert(m_input_unit[in_port]->isReady(invc) == false); // This Input VC should now be empty

                                        m_input_unit[in_port]->set_vc_state(IDLE_, invc);
                                        m_input_unit[in_port]->set_enqueue_time(invc, INFINITE_);
                                }
                                else
                                {
                                        m_input_unit[in_port]->increment_credit(invc, false); // Send a credit back but do not indicate that the VC is idle
                                }
                                break; // got a in request for this outport
                        }
                }
        }
}

void SWallocator_d::check_for_wakeup()
{
        for(int i = 0; i < m_num_inports; i++)
        {
                for(int j = 0; j < m_num_vcs; j++)
                {
                        if(m_input_unit[i]->need_stage_nextcycle(j, ACTIVE_, SA_))
                        {
                                g_eventQueue_ptr->scheduleEvent(this, 1);
                                return;
                        }
                }
        }
}

int SWallocator_d::get_vnet(int invc)
{
  for(int i = 0; i < RubySystem::getNetwork()->getNumberOfVirtualNetworks(); i++)
        {
                if(invc >= (i*m_vc_per_vnet) && invc < ((i+1)*m_vc_per_vnet))
                {
                        return i;
                }
        }
        ERROR_MSG("Could not determine vc");
        return -1;
}

void SWallocator_d::clear_request_vector()
{
        for(int i = 0; i < m_num_outports; i++)
        {
                for(int j = 0; j < m_num_inports; j++)
                {
                        m_port_req[i][j] = false;
                }
        }
}
